On Tuesday, May 18th, President Obama will formally begin one of the greatest bait-and-switch operations since the fabled "Emperor's New Clothes." With high-profile appearances before the Senate Foreign Relations Committee by his Secretaries of State and Defense and the Chairman of the Joint Chiefs of Staff, he will try to persuade Senators to vote for the defective New Strategic Arms Reduction Treaty (New START).

The real agenda is different, and worse, however: It is about getting buy-in from legislators for the President's policy of global denuclearization - for which New START is said to be an important building block.

Mr. Obama has good reason to try to obfuscate his true purposes. A debate I had last week with two of the premier champions of the President's pursuit of a "world without nuclear weapons" made clear how ill-advised and actually counterproductive is the effort now being made by the United States to advance this objective.

The debate was sponsored by the American Society of International Lawyers and the United Nations Association and represented, to my knowledge, the first time the proposition had been squarely joined in a public setting. It was supposed to involve just retired Career Ambassador Thomas Pickering and me, but wound up featuring as well comments from one of the prime-movers behind the denuclearization initiative, former Reagan strategic arms negotiator Max Kampelman.

It turned out that the proponents of a world free of nuclear arms were long on aspiration and short on credible responses to my contention that common sense dictates such an end state would not be desirable, even if it somehow could be achieved. Hard experience suggests that such an international environment would be prone to renewed cataclysms of the kind that afflicted the planet twice in the last century, at the cost of tens of millions of lives.

Messrs. Pickering and Kampelman were no more convincing on the mechanics of eliminating all nuclear weapons, given the widespread availability of the relevant technology and know-how and the ease with which small arsenals could be concealed by dictators ruling closed societies.

Such are, in a manner of speaking, "the President's new clothes."

In fact, the most striking thing about the proponents' presentations was their profession - in the face of the foregoing objections - that they merely favored a "close look" at the idea of ridding the globe of nuclear weapons. I was obliged repeatedly to point out that, while I would have no objection to doing that, we were well past such an exercise: The President has formally and repeatedly declared that it is the policy of the United States to bring about a world without nuclear arms. And he views New START as not just evidence of America's commitment to doing just that; it is also an important means of advancing that aim.

Which brings us to the testimony Tuesday on Capitol Hill. The main thrust - at least of the Pentagon leaders' portion - was telegraphed in an op.ed. published in the Wall Street Journal last week by Secretary of Defense Robert Gates. It crowed that an $80 billion "modernization" program would be implemented over the next ten years alongside the New START accord.

How to square this vast expenditure with the President's determination to "devalue" nuclear weapons and move America toward zero? This is where the bait-and-switch comes in. Forty-one Senators wrote Mr. Obama in December stating that they would not be able to vote for any new START accord unless it were accompanied by a comprehensive modernization plan. That's seven more than are needed to block ratification; with Scott Brown's addition to the Senate, there are probably forty-two legislators who will insist that the nation's nuclear deterrent be upgraded.

What is more, since virtually every member of the U.S. Senate will profess (as, by the way, does Barack Obama), that we will need to maintain that deterrent for the foreseeable future (the President says for the rest of his lifetime), the administration has to be seen as doing something about a natty reality: Our nuclear weapons are, on average, 30 years-old and have not been realistically tested since 1992. Hence the $80 billion, ten-year "modernization" program.

The trouble is that President Obama says that expenditure will not buy a single new weapon. Nor will any of it go towards testing the ones we have by exploding any of them underground - the only way to be absolutely certain they work. Neither will we reestablish the industrial base to build more than a handful of weapons. Similarly, we will not actually manufacture any new bombers or missile launchers on land or at sea to replace the aging ones now in the force.

What we will do, though, is communicate the President's commitment to the devaluing of the nuclear mission and enterprise. Particularly when combined with the foregoing restrictions, such a message is certain to encourage the high-quality scientists, engineers and technicians upon whom our deterrent critically depends to find other work.

Senators must explore New START's myriad other problems - including its inequitable limits, strategically ominous constraints on U.S. missile defenses and non-nuclear systems, inadequate verification, etc. But their main job should be to lay bare the underlying, unacceptable and deliberately obscured proposition: If ratified, this treaty will implicate the Senate in a radical, wooly-headed disarmament agenda that has at its core the unilateral denuclearization of the United States through the unchecked atrophying of its arsenal.